Yeah, Mega Evolution is not automatic. You have to:
1) Have that bracelet thing from Korrina
2) Have the Pokemon hold the particular item, like Lucarionite
3) During the battle, click on the "Mega Evolution!" button, then select an attack
4) Pokemon will Mega Evolve, then use the attack, then stay Mega Evolved until... I forget if it is until the end of the battle or until you swap out. Those have usually been the same thing for me so far with it.

Well, I always have been, and remain, sceptical of Mega Evolutions, thusly I think their inclusion would harm the game overall. From a coding standpoint, including them would be incredibly hard (take it from (one of?) the only person/people here who has/have tried to implement formes in battle!) and that's ignoring the more obvious issues with needing to change the battle UI based on whether it's holding the item.

The diagonal movement could be achieved fairly easily from a technical standpoint, but it opens up a whole can of worms with being able to skip events and such, since the game is obviously not designed for such movement. Overall, not something I'd consider worthwhile.

The other things are really just extensions of existing research and development and as such can be implemented fairly easily.

4) Pokemon will Mega Evolve, then use the attack, then stay Mega Evolved until... I forget if it is until the end of the battle or until you swap out. Those have usually been the same thing for me so far with it.

Actually, the Mega Evolution sequence always goes first no matter what, but if the opponent has a higher speed then you, your opponent will attack immediately after you Mega Evolve. Like, let's say we have a Charizard w/ Charizardite X, vs. a very fast Electrode that has a higher speed than the Charizard. The events would play out in this order:
1. Charizard Mega Evolves
2. Electrode attacks, due to having higher speed
3. Mega Charizard attacks

Also the Mega Evolution stays until the end of the battle, even if you switch it out.

Quote:

Originally Posted by Jambo51

Well, I always have been, and remain, sceptical of Mega Evolutions,

Talking strictly about the concept itself rather than the mechanics behind it, I would just like to point out that Game Freak didn't invent Mega Evolutions because "they look cool", Game Freak invented Mega Evolutions to enable certain Pokemon that suck in-battle to not suck as much anymore. Sure, you could argue that they could have just buffed their stats, which they actually did to a lot of Pokemon in X/Y, but only to give them a +10 in their Base Stat Total, while Mega Evolution gives the Pokemon a +100 in their Base Stat Total.

Actually, the Mega Evolution sequence always goes first no matter what, but if the opponent has a higher speed then you, your opponent will attack immediately after you Mega Evolve. Like, let's say we have a Charizard w/ Charizardite X, vs. a very fast Electrode that has a higher speed than the Charizard. The events would play out in this order:
1. Charizard Mega Evolves
2. Electrode attacks, due to having higher speed
3. Mega Charizard attacks

Also the Mega Evolution stays until the end of the battle, even if you switch it out.

Now that you mention it, yeah I do remember the other Pokemon attacking first sometimes after I mega evolved Lucario.

Talking strictly about the concept itself rather than the mechanics behind it, I would just like to point out that Game Freak didn't invent Mega Evolutions because "they look cool", Game Freak invented Mega Evolutions to enable certain Pokemon that suck in-battle to not suck as much anymore. Sure, you could argue that they could have just buffed their stats, which they actually did to a lot of Pokemon in X/Y, but only to give them a +10 in their Base Stat Total, while Mega Evolution gives the Pokemon a +100 in their Base Stat Total.

Then perhaps Game Freak should have balanced the games better to begin with, instead of "inventing" (as you claim, when it is in fact an idea stolen wholesale from inferior Pokémon clones) a workaround. Certain Pokémon need to be weak, it makes no sense for them to all be balanced nicely, it actually breaks the whole appeal of the game for me, being able to capture, train and eventually trade out for something better.

Then perhaps Game Freak should have balanced the games better to begin with, instead of "inventing" (as you claim, when it is in fact an idea stolen wholesale from inferior Pokémon clones) a workaround. Certain Pokémon need to be weak, it makes no sense for them to all be balanced nicely, it actually breaks the whole appeal of the game for me, being able to capture, train and eventually trade out for something better.

it makes no sense for them to all be balanced nicely, it actually breaks the whole appeal of the game for me, being able to capture, train and eventually trade out for something better.